2 % (c) The GRASP/AQUA Project, Glasgow University, 1999
4 \section[ParseUtil]{Parser Utilities}
8 parseError -- String -> Pa
9 , srcParseErr -- StringBuffer -> SrcLoc -> Message
11 , splitForConApp -- RdrNameHsType -> [RdrNameBangType]
12 -- -> P (RdrName, [RdrNameBangType])
14 , mkRecConstrOrUpdate -- HsExp -> [HsFieldUpdate] -> P HsExp
17 , mkExtName -- Maybe ExtName -> RdrName -> ExtName
19 , checkPrec -- String -> P String
20 , checkContext -- HsType -> P HsContext
21 , checkInstType -- HsType -> P HsType
22 , checkAssertion -- HsType -> P HsAsst
23 , checkDataHeader -- HsQualType -> P (HsContext,HsName,[HsName])
24 , checkSimple -- HsType -> [HsName] -> P ((HsName,[HsName]))
25 , checkPattern -- HsExp -> P HsPat
26 , checkPatterns -- [HsExp] -> P [HsPat]
27 -- , checkExpr -- HsExp -> P HsExp
28 , checkValDef -- (SrcLoc, HsExp, HsRhs, [HsDecl]) -> P HsDecl
31 -- some built-in names (all :: RdrName)
32 , unitCon_RDR, unitTyCon_RDR, nilCon_RDR, listTyCon_RDR
33 , tupleCon_RDR, tupleTyCon_RDR, ubxTupleCon_RDR, ubxTupleTyCon_RDR
36 -- pseudo-keywords, in var and tyvar forms (all :: RdrName)
37 , as_var_RDR, hiding_var_RDR, qualified_var_RDR, forall_var_RDR
38 , export_var_RDR, label_var_RDR, dynamic_var_RDR, unsafe_var_RDR
39 , stdcall_var_RDR, ccall_var_RDR
41 , as_tyvar_RDR, hiding_tyvar_RDR, qualified_tyvar_RDR
42 , export_tyvar_RDR, label_tyvar_RDR, dynamic_tyvar_RDR
43 , unsafe_tyvar_RDR, stdcall_tyvar_RDR, ccall_tyvar_RDR
45 , minus_RDR, pling_RDR, dot_RDR
49 #include "HsVersions.h"
57 import PrelMods ( pRELUDE_Name, mkUbxTupNameStr, mkTupNameStr )
58 import OccName ( dataName, tcName, varName, tvName, setOccNameSpace, occNameFS )
59 import CmdLineOpts ( opt_NoImplicitPrelude )
60 import StringBuffer ( lexemeToString )
61 import FastString ( unpackFS )
63 import UniqFM ( UniqFM, listToUFM, lookupUFM )
66 -----------------------------------------------------------------------------
69 parseError :: String -> P a
71 getSrcLocP `thenP` \ loc ->
72 failMsgP (hcat [ppr loc, text ": ", text s])
74 srcParseErr :: StringBuffer -> SrcLoc -> Message
78 then ptext SLIT(": parse error (possibly incorrect indentation)")
79 else hcat [ptext SLIT(": parse error on input "),
80 char '`', text token, char '\'']
83 token = lexemeToString s
85 cbot = panic "CCall:result_ty"
87 -----------------------------------------------------------------------------
90 -- When parsing data declarations, we sometimes inadvertently parse
91 -- a constructor application as a type (eg. in data T a b = C a b `D` E a b)
92 -- This function splits up the type application, adds any pending
93 -- arguments, and converts the type constructor back into a data constructor.
95 splitForConApp :: RdrNameHsType -> [RdrNameBangType]
96 -> P (RdrName, [RdrNameBangType])
98 splitForConApp t ts = split t ts
100 split (MonoTyApp t u) ts = split t (Unbanged u : ts)
102 split (MonoTyVar t) ts = returnP (con, ts)
103 where t_occ = rdrNameOcc t
104 con = setRdrNameOcc t (setOccNameSpace t_occ dataName)
106 split _ _ = parseError "Illegal data/newtype declaration"
108 ----------------------------------------------------------------------------
109 -- Various Syntactic Checks
111 callConvFM :: UniqFM CallConv
112 callConvFM = listToUFM $
113 map (\ (x,y) -> (_PK_ x,y))
114 [ ("stdcall", stdCallConv),
116 -- ("pascal", pascalCallConv),
117 -- ("fastcall", fastCallConv)
120 checkCallConv :: FAST_STRING -> P CallConv
122 case lookupUFM callConvFM s of
123 Nothing -> parseError ("unknown calling convention: `"
124 ++ unpackFS s ++ "'")
125 Just conv -> returnP conv
127 checkInstType :: RdrNameHsType -> P RdrNameHsType
130 HsForAllTy tvs ctxt ty ->
131 checkAssertion ty [] `thenP` \(c,ts)->
132 returnP (HsForAllTy tvs ctxt (MonoDictTy c ts))
134 ty -> checkAssertion ty [] `thenP` \(c,ts)->
135 returnP (HsForAllTy Nothing [] (MonoDictTy c ts))
137 checkContext :: RdrNameHsType -> P RdrNameContext
138 checkContext (MonoTupleTy ts True)
139 = mapP (\t -> checkAssertion t []) ts `thenP` \cs ->
141 checkContext (MonoTyVar t) -- empty contexts are allowed
142 | t == unitTyCon_RDR = returnP []
144 = checkAssertion t [] `thenP` \c ->
147 checkAssertion :: RdrNameHsType -> [RdrNameHsType]
148 -> P (ClassAssertion RdrName)
149 checkAssertion (MonoTyVar t) args@(_:_) | not (isRdrTyVar t)
151 checkAssertion (MonoTyApp l r) args = checkAssertion l (r:args)
152 checkAssertion _ _ = parseError "Illegal class assertion"
154 checkDataHeader :: RdrNameHsType
155 -> P (RdrNameContext, RdrName, [RdrNameHsTyVar])
156 checkDataHeader (HsForAllTy Nothing cs t) =
157 checkSimple t [] `thenP` \(c,ts) ->
158 returnP (cs,c,map UserTyVar ts)
160 checkSimple t [] `thenP` \(c,ts) ->
161 returnP ([],c,map UserTyVar ts)
163 checkSimple :: RdrNameHsType -> [RdrName] -> P ((RdrName,[RdrName]))
164 checkSimple (MonoTyApp l (MonoTyVar a)) xs | isRdrTyVar a
165 = checkSimple l (a:xs)
166 checkSimple (MonoTyVar t) xs | not (isRdrTyVar t) = returnP (t,xs)
167 checkSimple t _ = trace (showSDoc (ppr t)) $ parseError "Illegal data/newtype declaration"
169 ---------------------------------------------------------------------------
170 -- Checking Patterns.
172 -- We parse patterns as expressions and check for valid patterns below,
173 -- nverting the expression into a pattern at the same time.
175 checkPattern :: RdrNameHsExpr -> P RdrNamePat
176 checkPattern e = checkPat e []
178 checkPatterns :: [RdrNameHsExpr] -> P [RdrNamePat]
179 checkPatterns es = mapP checkPattern es
181 checkPat :: RdrNameHsExpr -> [RdrNamePat] -> P RdrNamePat
182 checkPat (HsVar c) args | isRdrDataCon c = returnP (ConPatIn c args)
183 checkPat (HsApp f x) args =
184 checkPat x [] `thenP` \x ->
186 checkPat e [] = case e of
187 EWildPat -> returnP WildPatIn
188 HsVar x -> returnP (VarPatIn x)
189 HsLit (HsLitLit _) -> patFail
190 HsLit l -> returnP (LitPatIn l)
191 ELazyPat e -> checkPat e [] `thenP` (returnP . LazyPatIn)
192 EAsPat n e -> checkPat e [] `thenP` (returnP . AsPatIn n)
193 ExprWithTySig e t -> checkPat e [] `thenP` \e ->
194 -- pattern signatures are parsed as sigtypes,
195 -- but they aren't explicit forall points. Hence
196 -- we have to remove the implicit forall here.
198 HsForAllTy Nothing [] ty -> ty
201 returnP (SigPatIn e t')
203 OpApp (HsVar n) (HsVar plus) _ (HsLit k@(HsInt _)) | plus == plus_RDR
204 -> returnP (NPlusKPatIn n k)
206 OpApp l op fix r -> checkPat l [] `thenP` \l ->
207 checkPat r [] `thenP` \r ->
209 HsVar c -> returnP (ConOpPatIn l c fix r)
212 NegApp l r -> checkPat l [] `thenP` (returnP . NegPatIn)
213 HsPar e -> checkPat e [] `thenP` (returnP . ParPatIn)
214 ExplicitList es -> mapP (\e -> checkPat e []) es `thenP` \ps ->
215 returnP (ListPatIn ps)
216 ExplicitTuple es b -> mapP (\e -> checkPat e []) es `thenP` \ps ->
217 returnP (TuplePatIn ps b)
218 RecordCon c fs -> mapP checkPatField fs `thenP` \fs ->
219 returnP (RecPatIn c fs)
222 checkPat _ _ = patFail
224 checkPatField :: (RdrName, RdrNameHsExpr, Bool)
225 -> P (RdrName, RdrNamePat, Bool)
226 checkPatField (n,e,b) =
227 checkPat e [] `thenP` \p ->
230 patFail = parseError "Parse error in pattern"
232 ---------------------------------------------------------------------------
233 -- Check Expression Syntax
236 We can get away without checkExpr if the renamer generates errors for
237 pattern syntax used in expressions (wildcards, as patterns and lazy
240 checkExpr :: RdrNameHsExpr -> P RdrNameHsExpr
241 checkExpr e = case e of
244 HsLam match -> checkMatch match `thenP` (returnP.HsLam)
245 HsApp e1 e2 -> check2Exprs e1 e2 HsApp
246 OpApp e1 e2 fix e3 -> checkExpr e1 `thenP` \e1 ->
247 checkExpr e2 `thenP` \e2 ->
248 checkExpr e3 `thenP` \e3 ->
249 returnP (OpApp e1 e2 fix e3)
250 NegApp e neg -> checkExpr e `thenP` \e ->
251 returnP (NegApp e neg)
252 HsPar e -> check1Expr e HsPar
253 SectionL e1 e2 -> check2Exprs e1 e2 SectionL
254 SectionR e1 e2 -> check2Exprs e1 e2 SectionR
255 HsCase e alts -> mapP checkMatch alts `thenP` \alts ->
256 checkExpr e `thenP` \e ->
257 returnP (HsCase e alts)
258 HsIf e1 e2 e3 -> check3Exprs e1 e2 e3 HsIf
260 HsLet bs e -> check1Expr e (HsLet bs)
261 HsDo stmts -> mapP checkStmt stmts `thenP` (returnP . HsDo)
262 HsTuple es -> checkManyExprs es HsTuple
263 HsList es -> checkManyExprs es HsList
264 HsRecConstr c fields -> mapP checkField fields `thenP` \fields ->
265 returnP (HsRecConstr c fields)
266 HsRecUpdate e fields -> mapP checkField fields `thenP` \fields ->
267 checkExpr e `thenP` \e ->
268 returnP (HsRecUpdate e fields)
269 HsEnumFrom e -> check1Expr e HsEnumFrom
270 HsEnumFromTo e1 e2 -> check2Exprs e1 e2 HsEnumFromTo
271 HsEnumFromThen e1 e2 -> check2Exprs e1 e2 HsEnumFromThen
272 HsEnumFromThenTo e1 e2 e3 -> check3Exprs e1 e2 e3 HsEnumFromThenTo
273 HsListComp e stmts -> mapP checkStmt stmts `thenP` \stmts ->
274 checkExpr e `thenP` \e ->
275 returnP (HsListComp e stmts)
276 RdrNameHsExprTypeSig loc e ty -> checkExpr e `thenP` \e ->
277 returnP (RdrNameHsExprTypeSig loc e ty)
278 _ -> parseError "parse error in expression"
280 -- type signature for polymorphic recursion!!
281 check1Expr :: RdrNameHsExpr -> (RdrNameHsExpr -> a) -> P a
282 check1Expr e f = checkExpr e `thenP` (returnP . f)
284 check2Exprs :: RdrNameHsExpr -> RdrNameHsExpr -> (RdrNameHsExpr -> RdrNameHsExpr -> a) -> P a
285 check2Exprs e1 e2 f =
286 checkExpr e1 `thenP` \e1 ->
287 checkExpr e2 `thenP` \e2 ->
290 check3Exprs :: RdrNameHsExpr -> RdrNameHsExpr -> RdrNameHsExpr -> (RdrNameHsExpr -> RdrNameHsExpr -> RdrNameHsExpr -> a) -> P a
291 check3Exprs e1 e2 e3 f =
292 checkExpr e1 `thenP` \e1 ->
293 checkExpr e2 `thenP` \e2 ->
294 checkExpr e3 `thenP` \e3 ->
297 checkManyExprs es f =
298 mapP checkExpr es `thenP` \es ->
301 checkAlt (HsAlt loc p galts bs)
302 = checkGAlts galts `thenP` \galts -> returnP (HsAlt loc p galts bs)
304 checkGAlts (HsUnGuardedAlt e) = check1Expr e HsUnGuardedAlt
305 checkGAlts (HsGuardedAlts galts)
306 = mapP checkGAlt galts `thenP` (returnP . HsGuardedAlts)
308 checkGAlt (HsGuardedAlt loc e1 e2) = check2Exprs e1 e2 (HsGuardedAlt loc)
310 checkStmt (HsGenerator p e) = check1Expr e (HsGenerator p)
311 checkStmt (HsQualifier e) = check1Expr e HsQualifier
312 checkStmt s@(HsLetStmt bs) = returnP s
314 checkField (HsFieldUpdate n e) = check1Expr e (HsFieldUpdate n)
315 checkField e = returnP e
317 ---------------------------------------------------------------------------
318 -- Check Equation Syntax
322 -> Maybe RdrNameHsType
325 -> P RdrNameMonoBinds
327 checkValDef lhs opt_sig grhss loc
328 = case isFunLhs lhs [] of
330 checkPatterns es `thenP` \ps ->
331 returnP (FunMonoBind f inf [Match [] ps opt_sig grhss] loc)
334 checkPattern lhs `thenP` \lhs ->
335 returnP (PatMonoBind lhs grhss loc)
337 -- A variable binding is parsed as an RdrNamePatBind.
339 isFunLhs (OpApp l (HsVar op) fix r) es | not (isRdrDataCon op)
340 = Just (op, True, (l:r:es))
341 isFunLhs (HsVar f) es@(_:_) | not (isRdrDataCon f)
343 isFunLhs (HsApp f e) es = isFunLhs f (e:es)
344 isFunLhs (HsPar e) es = isFunLhs e es
345 isFunLhs _ _ = Nothing
347 ---------------------------------------------------------------------------
348 -- Miscellaneous utilities
350 checkPrec :: Integer -> P ()
351 checkPrec i | 0 <= i && i <= 9 = returnP ()
352 | otherwise = parseError "precedence out of range"
356 -> RdrNameHsRecordBinds
359 mkRecConstrOrUpdate (HsVar c) fs | isRdrDataCon c
360 = returnP (RecordCon c fs)
361 mkRecConstrOrUpdate exp fs@(_:_)
362 = returnP (RecordUpd exp fs)
363 mkRecConstrOrUpdate _ _
364 = parseError "Empty record update"
366 -- supplying the ext_name in a foreign decl is optional ; if it
367 -- isn't there, the Haskell name is assumed. Note that no transformation
368 -- of the Haskell name is then performed, so if you foreign export (++),
369 -- it's external name will be "++". Too bad.
370 mkExtName :: Maybe ExtName -> RdrName -> ExtName
371 mkExtName Nothing rdrNm = ExtName (occNameFS (rdrNameOcc rdrNm)) Nothing
372 mkExtName (Just x) _ = x
374 -----------------------------------------------------------------------------
375 -- group function bindings into equation groups
377 -- we assume the bindings are coming in reverse order, so we take the srcloc
378 -- from the *last* binding in the group as the srcloc for the whole group.
380 groupBindings :: [RdrBinding] -> RdrBinding
381 groupBindings binds = group Nothing binds
382 where group :: Maybe RdrNameMonoBinds -> [RdrBinding] -> RdrBinding
383 group (Just bind) [] = RdrValBinding bind
384 group Nothing [] = RdrNullBind
385 group (Just (FunMonoBind f inf1 mtchs ignore_srcloc))
386 (RdrValBinding (FunMonoBind f' _ [mtch] loc) : binds)
387 | f == f' = group (Just (FunMonoBind f inf1 (mtch:mtchs) loc)) binds
389 group (Just so_far) binds
390 = RdrValBinding so_far `RdrAndBindings` group Nothing binds
391 group Nothing (bind:binds)
393 RdrValBinding b@(FunMonoBind _ _ _ _) -> group (Just b) binds
394 other -> bind `RdrAndBindings` group Nothing binds
396 -----------------------------------------------------------------------------
399 unitCon_RDR, unitTyCon_RDR, nilCon_RDR, listTyCon_RDR :: RdrName
400 tupleCon_RDR, tupleTyCon_RDR :: Int -> RdrName
401 ubxTupleCon_RDR, ubxTupleTyCon_RDR :: Int -> RdrName
404 | opt_NoImplicitPrelude = mkSrcUnqual dataName unitName
405 | otherwise = mkPreludeQual dataName pRELUDE_Name unitName
408 | opt_NoImplicitPrelude = mkSrcUnqual tcName unitName
409 | otherwise = mkPreludeQual tcName pRELUDE_Name unitName
412 | opt_NoImplicitPrelude = mkSrcUnqual dataName listName
413 | otherwise = mkPreludeQual dataName pRELUDE_Name listName
416 | opt_NoImplicitPrelude = mkSrcUnqual tcName listName
417 | otherwise = mkPreludeQual tcName pRELUDE_Name listName
420 | opt_NoImplicitPrelude = mkSrcUnqual tcName funName
421 | otherwise = mkPreludeQual tcName pRELUDE_Name funName
424 | opt_NoImplicitPrelude = mkSrcUnqual dataName (snd (mkTupNameStr arity))
425 | otherwise = mkPreludeQual dataName pRELUDE_Name
426 (snd (mkTupNameStr arity))
429 | opt_NoImplicitPrelude = mkSrcUnqual tcName (snd (mkTupNameStr arity))
430 | otherwise = mkPreludeQual tcName pRELUDE_Name
431 (snd (mkTupNameStr arity))
434 ubxTupleCon_RDR arity
435 | opt_NoImplicitPrelude = mkSrcUnqual dataName (snd (mkUbxTupNameStr arity))
436 | otherwise = mkPreludeQual dataName pRELUDE_Name
437 (snd (mkUbxTupNameStr arity))
439 ubxTupleTyCon_RDR arity
440 | opt_NoImplicitPrelude = mkSrcUnqual tcName (snd (mkUbxTupNameStr arity))
441 | otherwise = mkPreludeQual tcName pRELUDE_Name
442 (snd (mkUbxTupNameStr arity))
444 unitName = SLIT("()")
445 funName = SLIT("(->)")
446 listName = SLIT("[]")
449 hidingName = SLIT("hiding")
450 qualifiedName = SLIT("qualified")
451 forallName = SLIT("forall")
452 exportName = SLIT("export")
453 labelName = SLIT("label")
454 dynamicName = SLIT("dynamic")
455 unsafeName = SLIT("unsafe")
456 stdcallName = SLIT("stdcall")
457 ccallName = SLIT("ccall")
459 as_var_RDR = mkSrcUnqual varName asName
460 hiding_var_RDR = mkSrcUnqual varName hidingName
461 qualified_var_RDR = mkSrcUnqual varName qualifiedName
462 forall_var_RDR = mkSrcUnqual varName forallName
463 export_var_RDR = mkSrcUnqual varName exportName
464 label_var_RDR = mkSrcUnqual varName labelName
465 dynamic_var_RDR = mkSrcUnqual varName dynamicName
466 unsafe_var_RDR = mkSrcUnqual varName unsafeName
467 stdcall_var_RDR = mkSrcUnqual varName stdcallName
468 ccall_var_RDR = mkSrcUnqual varName ccallName
470 as_tyvar_RDR = mkSrcUnqual tvName asName
471 hiding_tyvar_RDR = mkSrcUnqual tvName hidingName
472 qualified_tyvar_RDR = mkSrcUnqual tvName qualifiedName
473 export_tyvar_RDR = mkSrcUnqual tvName exportName
474 label_tyvar_RDR = mkSrcUnqual tvName labelName
475 dynamic_tyvar_RDR = mkSrcUnqual tvName dynamicName
476 unsafe_tyvar_RDR = mkSrcUnqual tvName unsafeName
477 stdcall_tyvar_RDR = mkSrcUnqual tvName stdcallName
478 ccall_tyvar_RDR = mkSrcUnqual tvName ccallName
480 minus_RDR = mkSrcUnqual varName SLIT("-")
481 pling_RDR = mkSrcUnqual varName SLIT("!")
482 dot_RDR = mkSrcUnqual varName SLIT(".")
484 plus_RDR = mkSrcUnqual varName SLIT("+")